Electrified vehicles, including hybrid, plug-in hybrid, and electric vehicles, are designed to be propelled or partially propelled by one or several electric machines, such as AC induction machines, DC brushless electric machines, and permanent magnetic synchronous machines. A battery pack is included in the electrified vehicles providing electricity to electric machines. Hybrid and plug-in hybrid vehicles also have built-in internal combustion engines, which are able to charge the battery pack and/or propel the electrified vehicle together with electric machines. The battery pack includes multiple battery cells in series and/or in parallel to achieve high voltage and/or high output power to meet the requirements of electric machines. The battery pack also provides power to other equipment and circuits inside of the electrified vehicle, such as the DC-DC converter, on-board generator, and air conditioning system.